BX mmm and rocks

[studway]

I just bought a BX 2350 with mmm to go along with a couple of larger old Fords to take care of our apple orchards and 2 acre garden. I thought I would just be using the 2350 mower for my home lawn and to do clean-up work around the stand at our PYO apple operation, but I'm finding it can handle a lot of the between-the-rows mowing that my 7' sickle bar doesn't get. And it does a much, much nicer job than our box mower does.

Here is my question: Has anyone broken their BX mmm by hitting rocks? What happened? what kind/size rock did the damage? How was it repaired? Cost? Hassle?

I ask because although our orchards are remarkably free of rocks, there are a few biggies out there and it is hard to remember the exact location of every single one of 'em. Many are the tips of buried boulders, which surely wouldn't budge if struck. So far, I have mowed about half the area where we have PYO without any problems, but I have been extremely cautious. I have actually hit a few tennis ball to softball-size rocks, and to my surprise, the blade just chopped them into smaller pieces.

Any thoughts appreciated. Thanks.

 

[islandman]

We have some rocks that seem to show up in our meadow also, so know what you're talking about on surprise rocks. I suggest that you mow the orchard at the 4 inch high deck setting to avoid problems, don't forget to set the wheels for the new height.

 

[studway]

We have some rocks that seem to show up in our meadow also, so know what you're talking about on surprise rocks. I suggest that you mow the orchard at the 4 inch high deck setting to avoid problems, don't forget to set the wheels for the new height.

Thanks islandman, but the box mower can get it down to about 4 inches. I've been using the mmm at 2.5 and 2.0 (believe it or not). The orchards are beginning to resemble a golf course, but l'm wondering what sort of repair bill I'll get if I break a shaft. I'm assuming, perhaps incorrectly, that the belt drive will protect the engine should the blade run up against an immovable object.

c'mon, I know there are some people who have broken their mmm on rocks.

 

[skipperbrown]

I nailed a veneer queen sized brick (like the kind our house is constructed with) w/ my mmm. It made a racket and put a small dent in a blade. The brick was dusted. The tractor acted like it was a blade of grass.

I think a limestone rock would present a greater challenge. The belt should allow the blade shaft to stop. I would think bend blades would be the biggest problem.

 

[albertsteurer]

I hit a 6 inch rock...it spit it out about 12 feet. Chipped the blade about 1/4 inch but no change in speed or balance of blades. So I guess I lucked out. Wouldn't want to do it every day though.

 

[edownr]

Although I have a B2910, the mmm deck construction is the same type. I can tell you from experience, hitting heavy objects with the mowing blades will must likely result in the key (half moon) that is between the pulleys and the spindle shafts being sheared or partially sheared. If only partially sheared and not discovered in time, the pulley will "wallow" on the shaft and ruin the pulley. If the key is totally sheared, the pulley will slip on the shaft and likely immediately noticed.
Of course, the key shearing is what is supposed to happen to protect the other expensive components.
I had this happen (partially sheared keys) to an outer pulley and the gearbox pulley at the same time. Didn't notice until the pulleys "wallowed" out and stated making strange noises! Quite a job to replace and expensive.
Larry

 

[studway]

I wish I only had brick and limestone to contend with. I'm in the granite state. Maybe I could paint all the rocks I find orange to help me avoid them.

 

[SeymourBota]

I wish I only had brick and limestone to contend with. I'm in the granite state. Maybe I could paint all the rocks I find orange to help me avoid them.

I, too, am in a "granite state". The first time through a field I think you have two choices- 1. have someone precede the tractor and watch for rocks or 2. rent/borrow something like a landscape rake that would alert you to them as it passed over.
Then, you could either mark them (I might use neon green paint, to alert me but not offend others) or remove them.

Last time I did this, I started high and then lowered by 1/2 inch settings each week until I got down to the lowest practical setting.
You might nick a rock at 3.5" and chip a blade rather than shear a key.

 

[HomeBrew2]

I'm not in THE granite state but we have mostly granite rocks here
Along with scouting on foot and using paint, I have let the FEL ride along the ground to do scouting for me. Also a little Roundup sprayed around notorious rocks help in seeing them next time.

 

[KirkMcD]

Here is my question: Has anyone broken their BX mmm by hitting rocks? What happened? what kind/size rock did the damage? How was it repaired? Cost? Hassle?

When ever I've hit a rock, of any size, I usually end up with a lot of little rocks and a nick in the blade.
If I'm brush hogging with the MMM, I usually only lower it half-way though.